To provide an optical connector promoting reliability by reducing insertion loss of an optical fiber and downsized, there is provided an optical connector plug having a ferrule including a cylindrical member for the ferrule for holding an optical fiber and a flange member provided at a rear end portion of the cylindrical member for the ferrule, an urge spring provided on a side of a rear end portion of the flange member of the ferrule, and a plug housing for holding the ferrule and the urge spring directly at inside thereof and directly engaged with an optical connector adapter inserted with a front end portion of the ferrule to carry out optical connection, in which the plug housing is formed with a slit capable of inserting the optical fiber in a radius direction thereof at a portion of an outer periphery thereof over an axial direction.